Great Britain's Will Stevens has joined Marussia as one of the team's official reserve drivers, alongside American racer Alexander Rossi.
Stevens, 23, has previous F1 experience, having tested for Caterham in both 2013 and earlier this year at Silverstone. Marussia said in a statement that he will take part in a "number of FP1 sessions during the remainder of the season".
"Will is a driver we have been watching since he arrived in Formula Renault. We have admired his ability to learn quickly and compete in the thick of the action, so we are very pleased to add him to our roster of Official Reserve Drivers, which is now looking very strong indeed," Marussia team principal John Booth said.
"It is great to be able to take such promising talents as Will and Alexander under our wing and help them progress to the next level. We look forward to seeing Will perform in the MR03, when I am sure he will demonstrate some further signs of his obvious potential."
Stevens added: "I'm really thrilled to be given this opportunity by the Marussia F1 Team. They are a great team, with enormous potential, and I'm so happy to be joining them at this exciting time in their development.
"Off the back of my F1 tests with Caterham, I can't wait to get my first taste of the MR03. I'm looking forward to rewarding their faith in me and to making a positive contribution to our progress in the 2014 championship, and beyond."
Stevens, who was formerly part of Caterham's junior driver programme at the beginning of the season, currently competes in Formula Renault 3.5. He lies sixth overall, with one victory and three podiums to his credit, after eight of this year's nine events.
Marussia have given Rossi one practice run so far this year, when he participated in FP1 in Belgium.
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